Okay, I read through the entire thing, so here are my thoughts:
I liked this more than I expected I would. There were things that really annoyed me - namely, the gratuitous Ecchi
scenes and the pacing, but in general I did like the characters and story.
I will agree that the last few chapters definitely seemed rushed, though. And Chapter 23 in particular seemed like it was throwing a bone to all of the readers that were shipping Miyaji and Yukimori, as if the author knew that he would piss them all off with the yuri ending. Hey, maybe that was why the manga ended up rushed - the magazine cancelled it because it was going more and more towards an actual yuri end!
As for the yuri itself, I'm really glad that the author went through to with it, especially when you look at the earlier chapters. Yukimori's and Sarina's relationship, while also kinda rushed, was still pretty enjoyable overall with them getting closer and Sarina's realization in Chapter 20. I do wish there was more time to develop it, and to just show them dating. That last panel of Chapter 20, with the closeted girl classmates secretly being happy about the kiss was a nice touch.
Finally, I was wondering - is there a Volume 4 Special? There were specials for the other volumes too, which is why I'm asking.